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J C Jaton

Publications and source records attributed to J C Jaton.

108 records · Page 6Linked to original sources
PubMed1970

Isolation and characterization of structurally homogeneous antibodies from antipneumococcal sera.

Antibodies of sufficient homogeneity for sequence studies were readily obtained in high concentrations from rabbits immunized with pneumococcal vaccines. By taking advantage of slightly differing immunologic specificity for Type III and Type VIII capsular polysaccharides, an antibody with unique electrophoretic mobility could be isolated from serum containing several distinct antibody components by using appropriate cross-reacting immunoadsorbents. A unique sequence for the N-terminal 11 amino acid residues of the light chain of the antibody was found, in contrast to several sequences in the antibody mixture from which this component was isolated. The sequence of a nonimmune light chain pool demonstrates even greater heterogeneity. Chymotryptic peptide maps of the antibody light chain show two unique cysteine-containing variable region peptides not seen in maps of nonimmune light chain pool of the same allotypic specificity as that of the antibody light chain. The experimental approach described here may provide further insight into the structure-function relationship of several homogeneous antibodies of closely related specificity for the same polysaccharide antigen.

Acetates↗
PubMed1969

The genetic control of antibody specificity.

The immune response to a synthetic polypeptide built on multichain polyproline, poly-L-(Tyr,Glu)-poly-L-Pro-poly-L-Lys [(T,G)-Pro--L], in the offspring of a cross between DBA/1 and SJL mice is under a genetic control superficially similar to the one operating for the immune response to a similar synthetic polypeptide built on multichain polyalanine, poly-L-(Tyr,Glu)-poly-D,L-Ala-poly-L-Lys [(T,G)-A--L], in the offspring of a cross between CBA and C57 mice. In both cases, the genetic control is a quantitative trait in which the major gene(s) is (are) dominant and the trait is not linked to any of the known structural genes coding for mouse immunoglobulin heavy chains. However, the genetic control of response to (T, G)-Pro--L, designated immune response-3 (Ir-3), is qualitatively different from the one operating for (T,G)-A--L [immune response-1 (Ir-1)] in that it is not linked to the histocompatibility-2 (H-2) locus. A study of the immune response to a related polypeptide built on multichain polyproline, poly-L-(Phe,Glu)-poly-L-Pro-poly-L--Lys [(Phe, G)-Pro--L], in the DBA/1 x SJL cross has shown a genetic control of antibody specificity. F(1) x DBA/1 backcross anti-(Phe, G)-Pro--L sera segregate in their ability to bind (T,G)-Pro--L, and there is no linkage of anti-(T,G)-Pro--L binding capacity with the H-2(s) allele of the SJL grandparent. F(1) x SJL anti-(Phe, G)-Pro-L sera segregate in their capacity to bind poly-L-(Phe,Glu)-poly-D,L-Ala-poly-L-Lys [(Phe, G)-A--L] and the ability to bind (Phe, G)-A--L is clearly linked to the H-2(q) allele from the DBA/1 grandparent. Thus, in mice all responding well to a given antigen [(Phe, G)-Pro--L], the specificity of the antibodies produced [i.e., anti-(Phe,G) or anti-prolyl] is genetically determined. Cross-inhibition of binding m (DBA/1 x SJL)F(1) anti-(Phe,G)-Pro--L antisera indicates that the anti-(Phe,G) and anti-prolyl specificities are a function of two separate and largely non-crossreacting antibody populations.

Alleles↗
PubMed1969

The nature of the antigenic determinant in a genetic control of the antibody response.

The response of inbred mouse strains to two polypeptides derived from multichain polyprolines, (T,G)-Pro--L and (Phe,G)-Pro--L, is different from the response of the same mouse strains to a similar series of polymers built on multi-poly-D,L-alanyl--poly-L-lysine, although the same short sequences of amino acids are attached to the side chains of the polypeptides in the two series. These results indicate that a portion of the side chain (e.g. polyalanine or polyproline) participates in the antigenic determinant. This was confirmed by studying the response of different mouse strains to two kinds of polypeptides: (T,G)-Pro-A--L 717 and 718 and (T,G)-A-Pro--L 719 and 721. Antibody assay of antisera to (Phe,G)-Pro--L with the cross-reacting antigens (T,G)-Pro--L and (Phe,G)-A-L indicates that different inbred mouse strains make antibodies specific for different parts of the same polypeptide. Thus, antibody from DBA/1 mice reacts almost exclusively with the (Phe,G) sequence, while SJL antisera bind only (T,G)-Pro--L and fail to bind (Phe,G)-A-L. The immune responses to the same amino acids on two different polypeptides (i.e. A--L and Pro--L) appear to be under separate genetic control.

Amino Acids↗
PubMedDate not supplied

Further structural studies of membrane-bound IgM heavy chain of normal mouse B lymphocytes and partial amino acid sequence in its C-terminal hydrophobic tail.

Comparative structural studies of membrane-bound (mu m) and secretory mu chains (mu s) obtained from normal mouse spleen B lymphocytes and plasma cells were performed on CNBr digests of biosynthetically labelled chains. The purified major CNBr fragments were further digested with trypsin or Staphylococcus aureus V8 protease, and analyzed by high pressure liquid chromatography. The data show that mu m and mu s chains exhibit a very similar if not identical polypeptide structure over most of the four constant domains (from position N151 through N551), but that, in contrast, the mu m-C-terminal tail is different from mu s and contains a very hydrophobic segment. A combination of proteolysis, hydrophobic absorption and partial N-terminal sequencing of the hydrophobic fragment of mu m revealed in this region of the molecule a portion of sequence in perfect agreement with the structure predicted from the nucleotide sequence of the corresponding cDNA. The sequence of the C-terminal residues of mu m, which is different from that of mu s, could not be established, because of an apparent heterogeneity of mu m chains probably due to a great susceptibility to proteolysis of their C-terminal extremity.

Amino Acid Sequence↗
PubMedDate not supplied

Recent studies of the interaction of rabbit dimeric IgA with its polymeric immunoglobulin receptor.

Rabbit secretory components (SC) constitute a highly heterogeneous population of glycoprotein molecules that are present in secretions as free or bound forms to polymeric immunoglobulins (Ig). Two SC families are known, one of high molecular weight (approximately equal to 80 Kd) composed of five (perhaps six) domains related to Ig variable domains, and one of low molecular weight (approximately equal to 55 Kd). An account of our most recent experimental data is reviewed in this article. We have shown: 1) that both the high and low Mr SC families possess the same relative avidity for binding to dimeric IgA of the g-subclass; 2) that the first NH2-terminal domain of SC derived from the high and low Mr polypeptides is necessary and sufficient for efficient non-covalent binding to dimeric IgA of the g-subclass; 3) that the low Mr SC polypeptide derives from the high Mr SC by the internal deletion of the entire second and third domains, suggesting that these domains are not involved in the binding reaction with polymeric Ig; 4) that the heterogeneity of rabbit secretory components is, in large part, due to the expression of several polymorphic forms (allotypes) susceptible to be recognized by specific alloantisera; the biochemical characterization of the three known SC allotypes (t61, t62 and t63) reveals that t62 and t63 are structurally very similar to each other and markedly divergent from the t61 homologue; 5) that by using non-cross-reactive alloantisera, the major immunodominant allotopes are confined within the COOH-terminal domains 3, 4 and 5 of SC; 6) that the location of the residues involved in the attachment of the carbohydrate unit within domain 1 varies according to the allotype: t61 is N-linked glycosylated at position 70, whereas about 75% of t62 molecules are devoid of sugars; the remaining 25% of t62 molecules are glycosylated at residue position 90; these oligosaccharide chain units are linked to asparagine residues in the acceptor site consensus sequence, Asn-X-Thr/Ser; 7) that the presence of the carbohydrate unit in domain 1 is not required for efficient binding of this domain to polymeric Ig: indeed, after enzymatic deglycosylation, domain 1 exhibits a relative binding avidity which is indistinguishable from that of the native glycosylated domain 1.

Amino Acid Sequence↗
PubMedDate not supplied

The relationship between hypervariable regions, antigen-binding specificity and the three-dimensional structure of antibodies.

The amino acid sequences of the V domains (VL + VH regions) of 3 antibodies raised to type III pneumococcal polysaccharide in individual outbred rabbits are reported. With the exception of the second hypervariable section of the L chains, these antibodies have very different sequences in the hypervariable segments of the V domains. Within the third hypervariable region of the H chain, each antibody has a different length. On the sole basis of the amino acid sequences of these three anti-pneumococcal antibodies, the results do not support the concept of a simple correlation between primary structure in the hypervariable sections (known to determine the shape of the combining site) and antigen-binding specificity. In view of the large number of amino acid interchanges in the hypervariable positions and because of the size difference between the rabbit H chains, it is likely that each anti-SIII H chain studied here represents the product of a different structural germ line gene. In contrast to such a complex immune response to a relatively simple polysaccharide antigen, an extensive structural uniformity has been observed in the heavy chains of mouse myeloma proteins with phosphorylcholine activity and a mu chain from a human Waldenström IgM endowed with the same activity. The finding of a very similar heavy chain variable region in two different species which are separated by about 75 million years in evolution favours the concept of stable transmission of variable region genes throughout evolution.

Amino Acid Sequence↗